ffi_stream.rs: Align buffers when importing arrays

[felipecrv]

Upstream PR: apache#7137

Discussion in arrow-adbc apache/arrow-adbc#2526

[gliga]

Maybe link to the PR you opened to the forked repo and also to an example that led us to discover the issue, e.g., https://github.com/EngineeringSoftware/use-arrow-adbc/blob/89d83a3e968a64b2831d2be5156b2773fe5990b4/src/snowflake_static.rs#L21

[felipecrv]

Maybe link to the PR you opened to the forked repo and also to an example that led us to discover the issue, e.g., https://github.com/EngineeringSoftware/use-arrow-adbc/blob/89d83a3e968a64b2831d2be5156b2773fe5990b4/src/snowflake_static.rs#L21

And I posted the full stack trace here as well apache/arrow-adbc#2526

[findepi]

gliga requested a review from findepi

thanks for the ping! as long as it's a backport of something that lands upstream there is no reason to have objections

the upstream PR looks simple but i have not enough context to approve or disapprove.

is the change testable?

[felipecrv]

is the change testable?

I tested it with arithmetic.slt and running slt with the ADBC driver. Before the change, it panics, after the change, it passes without any problem.

I tried writing a test, but it would take a lot of work to create a RecordBatchReader in Rust that contains unaligned buffers because the factories of record batch readers take typed arrow arrays. By that point, all buffers are aligned.

[felipecrv]

Discussion is evolving in apache/arrow-adbc#2526. I will merge this because this enables progress on our side while the community at large decides on the final solution.

[findepi]

I tried writing a test, but it would take a lot of work to create a RecordBatchReader in Rust that contains unaligned buffers because the factories of record batch readers take typed arrow arrays.

it it possible to create buffers from arbitrary *u8 / NonNull<u8> pointers?

[findepi]

Discussion is evolving in apache/arrow-adbc#2526. I will merge this because this enables progress on our side while the community at large decides on the final solution.

👍

let's hope the community converges on a solution (!= wontfix)

[felipecrv]

I tried writing a test, but it would take a lot of work to create a RecordBatchReader in Rust that contains unaligned buffers because the factories of record batch readers take typed arrow arrays.

it it possible to create buffers from arbitrary *u8 / NonNull<u8> pointers?

Creating the buffers is easy, instantiating the <Typed>Array -> dyn Array -> RecordBatch -> RecordBatchReader is the challenging part because as soon as you create an array the alignment is validated.